The invention relates to a method and an arrangement for operating a drive unit of a vehicle.
A torque-orientated engine control is known from U.S. patent application Ser. No. 09/051,340, filed Apr. 6, 1998, wherein a driver command torque is formed on the basis of the position of an operator element, which is actuated by the driver, and, if needed, at least one further operating variable. The desired torque for the adjustment of the torque of the drive unit is derived from this driver command torque. From this command torque, a desired torque for adjusting the torque of the drive unit is derived which, in the case of an internal combustion engine, leads to a corresponding influencing of the air supply, the ignition angle and/or the fuel metering. To improve comfort, the desired torque is filtered with a pregiven filter function.
In this context, situations can occur in the dynamic operating state wherein the adjusted torque and the driver command torque differ from one another. However, if in such a situation filtering takes place and the filtered desired torque is adjusted as rapidly as possible, then a jump in the course of the torque occurs when this rapid torque adjustment is enabled and this can affect the comfort of the control. The above situation can, for example, take place in the case of an internal combustion engine by controlling the ignition angle, the air/fuel ratio and/or by suppression of individual injections.
It is the object of the invention to provide measures by which the comfort of the torque control is improved.
The basic structure of a torque-orientated control system for an internal combustion engine is known from DE-A 42 39 711 (U.S. Pat. No. 5,558,178).
It is known from EP-A 631 897 to detect a change of load situation and to thereupon undertake a limiting of the rate of change of the speed of the accelerator pedal positioning signal. Here too, the above-mentioned problems occur.
By initializing a desired value filter at the start of filtering with the actual value, a jump-shaped course of the actual value is effectively prevented which occurs when the actual value and the desired value differ at the start of filtering.
The application is especially advantageous in connection with a torque-orientated engine control wherein a driver command torque is formed on the basis of the actuating signal of an operator-controlled element. The actuating signal is filtered at least in one operating state and is adjusted in dependence upon the filtered value by controlling at least one power parameter of the drive unit.
Special advantages result when a rapid adjustment of the desired value takes place by, for example, control of the ignition angle and/or of the fuel metering. In this case, no torque jump occurs at the start of filtering.